2) Working alone, Rob can dig a 10 ft by 10 ft hole in ten hours. Shayna can dig the same hole in seven hours. Find how long it would take them if they worked together.​

Respuesta :

rob can dig 1/10ft in one hour

Shayna can dig 1/7ft in one our

together they can dig

1/10+1/7

(7+10)/70 in one hour

17/70

in for hours they can dig

17/70×4

68/70

the left work is 2/70

in 60 minutes they can dig 17/70

1/70 work can be done in 60 minutes/17

2/70 work can be done in 60/17×2 minutes

7.088 minutes

for the entire work they take 4hours and 7 minutes